package org.bouncycastle.crypto.digests;

import org.bouncycastle.crypto.util.Pack;

/**
 * FIPS 180-2 implementation of SHA-384.
 * 
 * <pre>
 *         block  word  digest
 * SHA-1   512    32    160
 * SHA-256 512    32    256
 * SHA-384 1024   64    384
 * SHA-512 1024   64    512
 * </pre>
 */
public class SHA384Digest extends LongDigest {

    private static final int DIGEST_LENGTH = 48;

    /**
     * Standard constructor
     */
    public SHA384Digest() {
    }

    /**
     * Copy constructor. This will copy the state of the provided message
     * digest.
     */
    public SHA384Digest(SHA384Digest t) {
        super(t);
    }

    public String getAlgorithmName() {
        return "SHA-384";
    }

    public int getDigestSize() {
        return DIGEST_LENGTH;
    }

    public int doFinal(byte[] out, int outOff) {
        finish();

        Pack.longToBigEndian(H1, out, outOff);
        Pack.longToBigEndian(H2, out, outOff + 8);
        Pack.longToBigEndian(H3, out, outOff + 16);
        Pack.longToBigEndian(H4, out, outOff + 24);
        Pack.longToBigEndian(H5, out, outOff + 32);
        Pack.longToBigEndian(H6, out, outOff + 40);

        reset();

        return DIGEST_LENGTH;
    }

    /**
     * reset the chaining variables
     */
    public void reset() {
        super.reset();

        /*
         * SHA-384 initial hash value The first 64 bits of the fractional parts
         * of the square roots of the 9th through 16th prime numbers
         */
        H1 = 0xcbbb9d5dc1059ed8l;
        H2 = 0x629a292a367cd507l;
        H3 = 0x9159015a3070dd17l;
        H4 = 0x152fecd8f70e5939l;
        H5 = 0x67332667ffc00b31l;
        H6 = 0x8eb44a8768581511l;
        H7 = 0xdb0c2e0d64f98fa7l;
        H8 = 0x47b5481dbefa4fa4l;
    }
}
